drivers/firmware/efi/libstub/x86-stub.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 /* -----------------------------------------------------------------------
   4  *
   5  *   Copyright 2011 Intel Corporation; author Matt Fleming
   6  *
   7  * ----------------------------------------------------------------------- */
   8
   9 #include <linux/efi.h>
  10 #include <linux/pci.h>
  11 #include <linux/stddef.h>
  12
  13 #include <asm/efi.h>
  14 #include <asm/e820/types.h>
  15 #include <asm/setup.h>
  16 #include <asm/desc.h>
  17 #include <asm/boot.h>
  18 #include <asm/kaslr.h>
  19 #include <asm/sev.h>
  20
  21 #include "efistub.h"
  22 #include "x86-stub.h"
  23
  24 const efi_system_table_t *efi_system_table;
  25 const efi_dxe_services_table_t *efi_dxe_table;
  26 static efi_loaded_image_t *image = NULL;
  27 static efi_memory_attribute_protocol_t *memattr;
  28
  29 typedef union sev_memory_acceptance_protocol sev_memory_acceptance_protocol_t;
  30 union sev_memory_acceptance_protocol {
  31         struct {
  32                 efi_status_t (__efiapi * allow_unaccepted_memory)(
  33                         sev_memory_acceptance_protocol_t *);
  34         };
  35         struct {
  36                 u32 allow_unaccepted_memory;
  37         } mixed_mode;
  38 };
  39
  40 static efi_status_t
  41 preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
  42 {
  43         struct pci_setup_rom *rom = NULL;
  44         efi_status_t status;
  45         unsigned long size;
  46         uint64_t romsize;
  47         void *romimage;
  48
  49         /*
  50          * Some firmware images contain EFI function pointers at the place where
  51          * the romimage and romsize fields are supposed to be. Typically the EFI
  52          * code is mapped at high addresses, translating to an unrealistically
  53          * large romsize. The UEFI spec limits the size of option ROMs to 16
  54          * MiB so we reject any ROMs over 16 MiB in size to catch this.
  55          */
  56         romimage = efi_table_attr(pci, romimage);
  57         romsize = efi_table_attr(pci, romsize);
  58         if (!romimage || !romsize || romsize > SZ_16M)
  59                 return EFI_INVALID_PARAMETER;
  60
  61         size = romsize + sizeof(*rom);
  62
  63         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
  64                              (void **)&rom);
  65         if (status != EFI_SUCCESS) {
  66                 efi_err("Failed to allocate memory for 'rom'\n");
  67                 return status;
  68         }
  69
  70         memset(rom, 0, sizeof(*rom));
  71
  72         rom->data.type  = SETUP_PCI;
  73         rom->data.len   = size - sizeof(struct setup_data);
  74         rom->data.next  = 0;
  75         rom->pcilen     = romsize;
  76         *__rom = rom;
  77
  78         status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
  79                                 PCI_VENDOR_ID, 1, &rom->vendor);
  80
  81         if (status != EFI_SUCCESS) {
  82                 efi_err("Failed to read rom->vendor\n");
  83                 goto free_struct;
  84         }
  85
  86         status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
  87                                 PCI_DEVICE_ID, 1, &rom->devid);
  88
  89         if (status != EFI_SUCCESS) {
  90                 efi_err("Failed to read rom->devid\n");
  91                 goto free_struct;
  92         }
  93
  94         status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus,
  95                                 &rom->device, &rom->function);
  96
  97         if (status != EFI_SUCCESS)
  98                 goto free_struct;
  99
 100         memcpy(rom->romdata, romimage, romsize);
 101         return status;
 102
 103 free_struct:
 104         efi_bs_call(free_pool, rom);
 105         return status;
 106 }
 107
 108 /*
 109  * There's no way to return an informative status from this function,
 110  * because any analysis (and printing of error messages) needs to be
 111  * done directly at the EFI function call-site.
 112  *
 113  * For example, EFI_INVALID_PARAMETER could indicate a bug or maybe we
 114  * just didn't find any PCI devices, but there's no way to tell outside
 115  * the context of the call.
 116  */
 117 static void setup_efi_pci(struct boot_params *params)
 118 {
 119         efi_status_t status;
 120         void **pci_handle = NULL;
 121         efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID;
 122         unsigned long size = 0;
 123         struct setup_data *data;
 124         efi_handle_t h;
 125         int i;
 126
 127         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 128                              &pci_proto, NULL, &size, pci_handle);
 129
 130         if (status == EFI_BUFFER_TOO_SMALL) {
 131                 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 132                                      (void **)&pci_handle);
 133
 134                 if (status != EFI_SUCCESS) {
 135                         efi_err("Failed to allocate memory for 'pci_handle'\n");
 136                         return;
 137                 }
 138
 139                 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 140                                      &pci_proto, NULL, &size, pci_handle);
 141         }
 142
 143         if (status != EFI_SUCCESS)
 144                 goto free_handle;
 145
 146         data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
 147
 148         while (data && data->next)
 149                 data = (struct setup_data *)(unsigned long)data->next;
 150
 151         for_each_efi_handle(h, pci_handle, size, i) {
 152                 efi_pci_io_protocol_t *pci = NULL;
 153                 struct pci_setup_rom *rom;
 154
 155                 status = efi_bs_call(handle_protocol, h, &pci_proto,
 156                                      (void **)&pci);
 157                 if (status != EFI_SUCCESS || !pci)
 158                         continue;
 159
 160                 status = preserve_pci_rom_image(pci, &rom);
 161                 if (status != EFI_SUCCESS)
 162                         continue;
 163
 164                 if (data)
 165                         data->next = (unsigned long)rom;
 166                 else
 167                         params->hdr.setup_data = (unsigned long)rom;
 168
 169                 data = (struct setup_data *)rom;
 170         }
 171
 172 free_handle:
 173         efi_bs_call(free_pool, pci_handle);
 174 }
 175
 176 static void retrieve_apple_device_properties(struct boot_params *boot_params)
 177 {
 178         efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID;
 179         struct setup_data *data, *new;
 180         efi_status_t status;
 181         u32 size = 0;
 182         apple_properties_protocol_t *p;
 183
 184         status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&p);
 185         if (status != EFI_SUCCESS)
 186                 return;
 187
 188         if (efi_table_attr(p, version) != 0x10000) {
 189                 efi_err("Unsupported properties proto version\n");
 190                 return;
 191         }
 192
 193         efi_call_proto(p, get_all, NULL, &size);
 194         if (!size)
 195                 return;
 196
 197         do {
 198                 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
 199                                      size + sizeof(struct setup_data),
 200                                      (void **)&new);
 201                 if (status != EFI_SUCCESS) {
 202                         efi_err("Failed to allocate memory for 'properties'\n");
 203                         return;
 204                 }
 205
 206                 status = efi_call_proto(p, get_all, new->data, &size);
 207
 208                 if (status == EFI_BUFFER_TOO_SMALL)
 209                         efi_bs_call(free_pool, new);
 210         } while (status == EFI_BUFFER_TOO_SMALL);
 211
 212         new->type = SETUP_APPLE_PROPERTIES;
 213         new->len  = size;
 214         new->next = 0;
 215
 216         data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
 217         if (!data) {
 218                 boot_params->hdr.setup_data = (unsigned long)new;
 219         } else {
 220                 while (data->next)
 221                         data = (struct setup_data *)(unsigned long)data->next;
 222                 data->next = (unsigned long)new;
 223         }
 224 }
 225
 226 void efi_adjust_memory_range_protection(unsigned long start,
 227                                         unsigned long size)
 228 {
 229         efi_status_t status;
 230         efi_gcd_memory_space_desc_t desc;
 231         unsigned long end, next;
 232         unsigned long rounded_start, rounded_end;
 233         unsigned long unprotect_start, unprotect_size;
 234
 235         rounded_start = rounddown(start, EFI_PAGE_SIZE);
 236         rounded_end = roundup(start + size, EFI_PAGE_SIZE);
 237
 238         if (memattr != NULL) {
 239                 efi_call_proto(memattr, clear_memory_attributes, rounded_start,
 240                                rounded_end - rounded_start, EFI_MEMORY_XP);
 241                 return;
 242         }
 243
 244         if (efi_dxe_table == NULL)
 245                 return;
 246
 247         /*
 248          * Don't modify memory region attributes, they are
 249          * already suitable, to lower the possibility to
 250          * encounter firmware bugs.
 251          */
 252
 253         for (end = start + size; start < end; start = next) {
 254
 255                 status = efi_dxe_call(get_memory_space_descriptor, start, &desc);
 256
 257                 if (status != EFI_SUCCESS)
 258                         return;
 259
 260                 next = desc.base_address + desc.length;
 261
 262                 /*
 263                  * Only system memory is suitable for trampoline/kernel image placement,
 264                  * so only this type of memory needs its attributes to be modified.
 265                  */
 266
 267                 if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory ||
 268                     (desc.attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0)
 269                         continue;
 270
 271                 unprotect_start = max(rounded_start, (unsigned long)desc.base_address);
 272                 unprotect_size = min(rounded_end, next) - unprotect_start;
 273
 274                 status = efi_dxe_call(set_memory_space_attributes,
 275                                       unprotect_start, unprotect_size,
 276                                       EFI_MEMORY_WB);
 277
 278                 if (status != EFI_SUCCESS) {
 279                         efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n",
 280                                  unprotect_start,
 281                                  unprotect_start + unprotect_size,
 282                                  status);
 283                 }
 284         }
 285 }
 286
 287 static void setup_unaccepted_memory(void)
 288 {
 289         efi_guid_t mem_acceptance_proto = OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL_GUID;
 290         sev_memory_acceptance_protocol_t *proto;
 291         efi_status_t status;
 292
 293         if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
 294                 return;
 295
 296         /*
 297          * Enable unaccepted memory before calling exit boot services in order
 298          * for the UEFI to not accept all memory on EBS.
 299          */
 300         status = efi_bs_call(locate_protocol, &mem_acceptance_proto, NULL,
 301                              (void **)&proto);
 302         if (status != EFI_SUCCESS)
 303                 return;
 304
 305         status = efi_call_proto(proto, allow_unaccepted_memory);
 306         if (status != EFI_SUCCESS)
 307                 efi_err("Memory acceptance protocol failed\n");
 308 }
 309
 310 static efi_char16_t *efistub_fw_vendor(void)
 311 {
 312         unsigned long vendor = efi_table_attr(efi_system_table, fw_vendor);
 313
 314         return (efi_char16_t *)vendor;
 315 }
 316
 317 static const efi_char16_t apple[] = L"Apple";
 318
 319 static void setup_quirks(struct boot_params *boot_params)
 320 {
 321         if (IS_ENABLED(CONFIG_APPLE_PROPERTIES) &&
 322             !memcmp(efistub_fw_vendor(), apple, sizeof(apple)))
 323                 retrieve_apple_device_properties(boot_params);
 324 }
 325
 326 /*
 327  * See if we have Universal Graphics Adapter (UGA) protocol
 328  */
 329 static efi_status_t
 330 setup_uga(struct screen_info *si, efi_guid_t *uga_proto, unsigned long size)
 331 {
 332         efi_status_t status;
 333         u32 width, height;
 334         void **uga_handle = NULL;
 335         efi_uga_draw_protocol_t *uga = NULL, *first_uga;
 336         efi_handle_t handle;
 337         int i;
 338
 339         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 340                              (void **)&uga_handle);
 341         if (status != EFI_SUCCESS)
 342                 return status;
 343
 344         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 345                              uga_proto, NULL, &size, uga_handle);
 346         if (status != EFI_SUCCESS)
 347                 goto free_handle;
 348
 349         height = 0;
 350         width = 0;
 351
 352         first_uga = NULL;
 353         for_each_efi_handle(handle, uga_handle, size, i) {
 354                 efi_guid_t pciio_proto = EFI_PCI_IO_PROTOCOL_GUID;
 355                 u32 w, h, depth, refresh;
 356                 void *pciio;
 357
 358                 status = efi_bs_call(handle_protocol, handle, uga_proto,
 359                                      (void **)&uga);
 360                 if (status != EFI_SUCCESS)
 361                         continue;
 362
 363                 pciio = NULL;
 364                 efi_bs_call(handle_protocol, handle, &pciio_proto, &pciio);
 365
 366                 status = efi_call_proto(uga, get_mode, &w, &h, &depth, &refresh);
 367                 if (status == EFI_SUCCESS && (!first_uga || pciio)) {
 368                         width = w;
 369                         height = h;
 370
 371                         /*
 372                          * Once we've found a UGA supporting PCIIO,
 373                          * don't bother looking any further.
 374                          */
 375                         if (pciio)
 376                                 break;
 377
 378                         first_uga = uga;
 379                 }
 380         }
 381
 382         if (!width && !height)
 383                 goto free_handle;
 384
 385         /* EFI framebuffer */
 386         si->orig_video_isVGA    = VIDEO_TYPE_EFI;
 387
 388         si->lfb_depth           = 32;
 389         si->lfb_width           = width;
 390         si->lfb_height          = height;
 391
 392         si->red_size            = 8;
 393         si->red_pos             = 16;
 394         si->green_size          = 8;
 395         si->green_pos           = 8;
 396         si->blue_size           = 8;
 397         si->blue_pos            = 0;
 398         si->rsvd_size           = 8;
 399         si->rsvd_pos            = 24;
 400
 401 free_handle:
 402         efi_bs_call(free_pool, uga_handle);
 403
 404         return status;
 405 }
 406
 407 static void setup_graphics(struct boot_params *boot_params)
 408 {
 409         efi_guid_t graphics_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
 410         struct screen_info *si;
 411         efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID;
 412         efi_status_t status;
 413         unsigned long size;
 414         void **gop_handle = NULL;
 415         void **uga_handle = NULL;
 416
 417         si = &boot_params->screen_info;
 418         memset(si, 0, sizeof(*si));
 419
 420         size = 0;
 421         status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 422                              &graphics_proto, NULL, &size, gop_handle);
 423         if (status == EFI_BUFFER_TOO_SMALL)
 424                 status = efi_setup_gop(si, &graphics_proto, size);
 425
 426         if (status != EFI_SUCCESS) {
 427                 size = 0;
 428                 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 429                                      &uga_proto, NULL, &size, uga_handle);
 430                 if (status == EFI_BUFFER_TOO_SMALL)
 431                         setup_uga(si, &uga_proto, size);
 432         }
 433 }
 434
 435
 436 static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status)
 437 {
 438         efi_bs_call(exit, handle, status, 0, NULL);
 439         for(;;)
 440                 asm("hlt");
 441 }
 442
 443 void __noreturn efi_stub_entry(efi_handle_t handle,
 444                                efi_system_table_t *sys_table_arg,
 445                                struct boot_params *boot_params);
 446
 447 /*
 448  * Because the x86 boot code expects to be passed a boot_params we
 449  * need to create one ourselves (usually the bootloader would create
 450  * one for us).
 451  */
 452 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 453                                    efi_system_table_t *sys_table_arg)
 454 {
 455         static struct boot_params boot_params __page_aligned_bss;
 456         struct setup_header *hdr = &boot_params.hdr;
 457         efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
 458         int options_size = 0;
 459         efi_status_t status;
 460         char *cmdline_ptr;
 461
 462         efi_system_table = sys_table_arg;
 463
 464         /* Check if we were booted by the EFI firmware */
 465         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 466                 efi_exit(handle, EFI_INVALID_PARAMETER);
 467
 468         status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image);
 469         if (status != EFI_SUCCESS) {
 470                 efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
 471                 efi_exit(handle, status);
 472         }
 473
 474         /* Assign the setup_header fields that the kernel actually cares about */
 475         hdr->root_flags = 1;
 476         hdr->vid_mode   = 0xffff;
 477
 478         hdr->type_of_loader = 0x21;
 479
 480         /* Convert unicode cmdline to ascii */
 481         cmdline_ptr = efi_convert_cmdline(image, &options_size);
 482         if (!cmdline_ptr)
 483                 goto fail;
 484
 485         efi_set_u64_split((unsigned long)cmdline_ptr, &hdr->cmd_line_ptr,
 486                           &boot_params.ext_cmd_line_ptr);
 487
 488         efi_stub_entry(handle, sys_table_arg, &boot_params);
 489         /* not reached */
 490
 491 fail:
 492         efi_exit(handle, status);
 493 }
 494
 495 static void add_e820ext(struct boot_params *params,
 496                         struct setup_data *e820ext, u32 nr_entries)
 497 {
 498         struct setup_data *data;
 499
 500         e820ext->type = SETUP_E820_EXT;
 501         e820ext->len  = nr_entries * sizeof(struct boot_e820_entry);
 502         e820ext->next = 0;
 503
 504         data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
 505
 506         while (data && data->next)
 507                 data = (struct setup_data *)(unsigned long)data->next;
 508
 509         if (data)
 510                 data->next = (unsigned long)e820ext;
 511         else
 512                 params->hdr.setup_data = (unsigned long)e820ext;
 513 }
 514
 515 static efi_status_t
 516 setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_size)
 517 {
 518         struct boot_e820_entry *entry = params->e820_table;
 519         struct efi_info *efi = &params->efi_info;
 520         struct boot_e820_entry *prev = NULL;
 521         u32 nr_entries;
 522         u32 nr_desc;
 523         int i;
 524
 525         nr_entries = 0;
 526         nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;
 527
 528         for (i = 0; i < nr_desc; i++) {
 529                 efi_memory_desc_t *d;
 530                 unsigned int e820_type = 0;
 531                 unsigned long m = efi->efi_memmap;
 532
 533 #ifdef CONFIG_X86_64
 534                 m |= (u64)efi->efi_memmap_hi << 32;
 535 #endif
 536
 537                 d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i);
 538                 switch (d->type) {
 539                 case EFI_RESERVED_TYPE:
 540                 case EFI_RUNTIME_SERVICES_CODE:
 541                 case EFI_RUNTIME_SERVICES_DATA:
 542                 case EFI_MEMORY_MAPPED_IO:
 543                 case EFI_MEMORY_MAPPED_IO_PORT_SPACE:
 544                 case EFI_PAL_CODE:
 545                         e820_type = E820_TYPE_RESERVED;
 546                         break;
 547
 548                 case EFI_UNUSABLE_MEMORY:
 549                         e820_type = E820_TYPE_UNUSABLE;
 550                         break;
 551
 552                 case EFI_ACPI_RECLAIM_MEMORY:
 553                         e820_type = E820_TYPE_ACPI;
 554                         break;
 555
 556                 case EFI_LOADER_CODE:
 557                 case EFI_LOADER_DATA:
 558                 case EFI_BOOT_SERVICES_CODE:
 559                 case EFI_BOOT_SERVICES_DATA:
 560                 case EFI_CONVENTIONAL_MEMORY:
 561                         if (efi_soft_reserve_enabled() &&
 562                             (d->attribute & EFI_MEMORY_SP))
 563                                 e820_type = E820_TYPE_SOFT_RESERVED;
 564                         else
 565                                 e820_type = E820_TYPE_RAM;
 566                         break;
 567
 568                 case EFI_ACPI_MEMORY_NVS:
 569                         e820_type = E820_TYPE_NVS;
 570                         break;
 571
 572                 case EFI_PERSISTENT_MEMORY:
 573                         e820_type = E820_TYPE_PMEM;
 574                         break;
 575
 576                 case EFI_UNACCEPTED_MEMORY:
 577                         if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
 578                                 continue;
 579                         e820_type = E820_TYPE_RAM;
 580                         process_unaccepted_memory(d->phys_addr,
 581                                                   d->phys_addr + PAGE_SIZE * d->num_pages);
 582                         break;
 583                 default:
 584                         continue;
 585                 }
 586
 587                 /* Merge adjacent mappings */
 588                 if (prev && prev->type == e820_type &&
 589                     (prev->addr + prev->size) == d->phys_addr) {
 590                         prev->size += d->num_pages << 12;
 591                         continue;
 592                 }
 593
 594                 if (nr_entries == ARRAY_SIZE(params->e820_table)) {
 595                         u32 need = (nr_desc - i) * sizeof(struct e820_entry) +
 596                                    sizeof(struct setup_data);
 597
 598                         if (!e820ext || e820ext_size < need)
 599                                 return EFI_BUFFER_TOO_SMALL;
 600
 601                         /* boot_params map full, switch to e820 extended */
 602                         entry = (struct boot_e820_entry *)e820ext->data;
 603                 }
 604
 605                 entry->addr = d->phys_addr;
 606                 entry->size = d->num_pages << PAGE_SHIFT;
 607                 entry->type = e820_type;
 608                 prev = entry++;
 609                 nr_entries++;
 610         }
 611
 612         if (nr_entries > ARRAY_SIZE(params->e820_table)) {
 613                 u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_table);
 614
 615                 add_e820ext(params, e820ext, nr_e820ext);
 616                 nr_entries -= nr_e820ext;
 617         }
 618
 619         params->e820_entries = (u8)nr_entries;
 620
 621         return EFI_SUCCESS;
 622 }
 623
 624 static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
 625                                   u32 *e820ext_size)
 626 {
 627         efi_status_t status;
 628         unsigned long size;
 629
 630         size = sizeof(struct setup_data) +
 631                 sizeof(struct e820_entry) * nr_desc;
 632
 633         if (*e820ext) {
 634                 efi_bs_call(free_pool, *e820ext);
 635                 *e820ext = NULL;
 636                 *e820ext_size = 0;
 637         }
 638
 639         status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 640                              (void **)e820ext);
 641         if (status == EFI_SUCCESS)
 642                 *e820ext_size = size;
 643
 644         return status;
 645 }
 646
 647 static efi_status_t allocate_e820(struct boot_params *params,
 648                                   struct setup_data **e820ext,
 649                                   u32 *e820ext_size)
 650 {
 651         struct efi_boot_memmap *map;
 652         efi_status_t status;
 653         __u32 nr_desc;
 654
 655         status = efi_get_memory_map(&map, false);
 656         if (status != EFI_SUCCESS)
 657                 return status;
 658
 659         nr_desc = map->map_size / map->desc_size;
 660         if (nr_desc > ARRAY_SIZE(params->e820_table) - EFI_MMAP_NR_SLACK_SLOTS) {
 661                 u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table) +
 662                                  EFI_MMAP_NR_SLACK_SLOTS;
 663
 664                 status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
 665         }
 666
 667         if (IS_ENABLED(CONFIG_UNACCEPTED_MEMORY) && status == EFI_SUCCESS)
 668                 status = allocate_unaccepted_bitmap(nr_desc, map);
 669
 670         efi_bs_call(free_pool, map);
 671         return status;
 672 }
 673
 674 struct exit_boot_struct {
 675         struct boot_params      *boot_params;
 676         struct efi_info         *efi;
 677 };
 678
 679 static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
 680                                    void *priv)
 681 {
 682         const char *signature;
 683         struct exit_boot_struct *p = priv;
 684
 685         signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
 686                                    : EFI32_LOADER_SIGNATURE;
 687         memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));
 688
 689         efi_set_u64_split((unsigned long)efi_system_table,
 690                           &p->efi->efi_systab, &p->efi->efi_systab_hi);
 691         p->efi->efi_memdesc_size        = map->desc_size;
 692         p->efi->efi_memdesc_version     = map->desc_ver;
 693         efi_set_u64_split((unsigned long)map->map,
 694                           &p->efi->efi_memmap, &p->efi->efi_memmap_hi);
 695         p->efi->efi_memmap_size         = map->map_size;
 696
 697         return EFI_SUCCESS;
 698 }
 699
 700 static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
 701 {
 702         struct setup_data *e820ext = NULL;
 703         __u32 e820ext_size = 0;
 704         efi_status_t status;
 705         struct exit_boot_struct priv;
 706
 707         priv.boot_params        = boot_params;
 708         priv.efi                = &boot_params->efi_info;
 709
 710         status = allocate_e820(boot_params, &e820ext, &e820ext_size);
 711         if (status != EFI_SUCCESS)
 712                 return status;
 713
 714         /* Might as well exit boot services now */
 715         status = efi_exit_boot_services(handle, &priv, exit_boot_func);
 716         if (status != EFI_SUCCESS)
 717                 return status;
 718
 719         /* Historic? */
 720         boot_params->alt_mem_k  = 32 * 1024;
 721
 722         status = setup_e820(boot_params, e820ext, e820ext_size);
 723         if (status != EFI_SUCCESS)
 724                 return status;
 725
 726         return EFI_SUCCESS;
 727 }
 728
 729 static bool have_unsupported_snp_features(void)
 730 {
 731         u64 unsupported;
 732
 733         unsupported = snp_get_unsupported_features(sev_get_status());
 734         if (unsupported) {
 735                 efi_err("Unsupported SEV-SNP features detected: 0x%llx\n",
 736                         unsupported);
 737                 return true;
 738         }
 739         return false;
 740 }
 741
 742 static void efi_get_seed(void *seed, int size)
 743 {
 744         efi_get_random_bytes(size, seed);
 745
 746         /*
 747          * This only updates seed[0] when running on 32-bit, but in that case,
 748          * seed[1] is not used anyway, as there is no virtual KASLR on 32-bit.
 749          */
 750         *(unsigned long *)seed ^= kaslr_get_random_long("EFI");
 751 }
 752
 753 static void error(char *str)
 754 {
 755         efi_warn("Decompression failed: %s\n", str);
 756 }
 757
 758 static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry)
 759 {
 760         unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
 761         unsigned long addr, alloc_size, entry;
 762         efi_status_t status;
 763         u32 seed[2] = {};
 764
 765         /* determine the required size of the allocation */
 766         alloc_size = ALIGN(max_t(unsigned long, output_len, kernel_total_size),
 767                            MIN_KERNEL_ALIGN);
 768
 769         if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
 770                 u64 range = KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR - kernel_total_size;
 771                 static const efi_char16_t ami[] = L"American Megatrends";
 772
 773                 efi_get_seed(seed, sizeof(seed));
 774
 775                 virt_addr += (range * seed[1]) >> 32;
 776                 virt_addr &= ~(CONFIG_PHYSICAL_ALIGN - 1);
 777
 778                 /*
 779                  * Older Dell systems with AMI UEFI firmware v2.0 may hang
 780                  * while decompressing the kernel if physical address
 781                  * randomization is enabled.
 782                  *
 783                  * https://bugzilla.kernel.org/show_bug.cgi?id=218173
 784                  */
 785                 if (efi_system_table->hdr.revision <= EFI_2_00_SYSTEM_TABLE_REVISION &&
 786                     !memcmp(efistub_fw_vendor(), ami, sizeof(ami))) {
 787                         efi_debug("AMI firmware v2.0 or older detected - disabling physical KASLR\n");
 788                         seed[0] = 0;
 789                 }
 790
 791                 boot_params_ptr->hdr.loadflags |= KASLR_FLAG;
 792         }
 793
 794         status = efi_random_alloc(alloc_size, CONFIG_PHYSICAL_ALIGN, &addr,
 795                                   seed[0], EFI_LOADER_CODE,
 796                                   EFI_X86_KERNEL_ALLOC_LIMIT);
 797         if (status != EFI_SUCCESS)
 798                 return status;
 799
 800         entry = decompress_kernel((void *)addr, virt_addr, error);
 801         if (entry == ULONG_MAX) {
 802                 efi_free(alloc_size, addr);
 803                 return EFI_LOAD_ERROR;
 804         }
 805
 806         *kernel_entry = addr + entry;
 807
 808         efi_adjust_memory_range_protection(addr, kernel_total_size);
 809
 810         return EFI_SUCCESS;
 811 }
 812
 813 static void __noreturn enter_kernel(unsigned long kernel_addr,
 814                                     struct boot_params *boot_params)
 815 {
 816         /* enter decompressed kernel with boot_params pointer in RSI/ESI */
 817         asm("jmp *%0"::"r"(kernel_addr), "S"(boot_params));
 818
 819         unreachable();
 820 }
 821
 822 /*
 823  * On success, this routine will jump to the relocated image directly and never
 824  * return.  On failure, it will exit to the firmware via efi_exit() instead of
 825  * returning.
 826  */
 827 void __noreturn efi_stub_entry(efi_handle_t handle,
 828                                efi_system_table_t *sys_table_arg,
 829                                struct boot_params *boot_params)
 830 {
 831         efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
 832         struct setup_header *hdr = &boot_params->hdr;
 833         const struct linux_efi_initrd *initrd = NULL;
 834         unsigned long kernel_entry;
 835         efi_status_t status;
 836
 837         boot_params_ptr = boot_params;
 838
 839         efi_system_table = sys_table_arg;
 840         /* Check if we were booted by the EFI firmware */
 841         if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 842                 efi_exit(handle, EFI_INVALID_PARAMETER);
 843
 844         if (have_unsupported_snp_features())
 845                 efi_exit(handle, EFI_UNSUPPORTED);
 846
 847         if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES)) {
 848                 efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID);
 849                 if (efi_dxe_table &&
 850                     efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) {
 851                         efi_warn("Ignoring DXE services table: invalid signature\n");
 852                         efi_dxe_table = NULL;
 853                 }
 854         }
 855
 856         /* grab the memory attributes protocol if it exists */
 857         efi_bs_call(locate_protocol, &guid, NULL, (void **)&memattr);
 858
 859         status = efi_setup_5level_paging();
 860         if (status != EFI_SUCCESS) {
 861                 efi_err("efi_setup_5level_paging() failed!\n");
 862                 goto fail;
 863         }
 864
 865 #ifdef CONFIG_CMDLINE_BOOL
 866         status = efi_parse_options(CONFIG_CMDLINE);
 867         if (status != EFI_SUCCESS) {
 868                 efi_err("Failed to parse options\n");
 869                 goto fail;
 870         }
 871 #endif
 872         if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
 873                 unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
 874                                                ((u64)boot_params->ext_cmd_line_ptr << 32));
 875                 status = efi_parse_options((char *)cmdline_paddr);
 876                 if (status != EFI_SUCCESS) {
 877                         efi_err("Failed to parse options\n");
 878                         goto fail;
 879                 }
 880         }
 881
 882         status = efi_decompress_kernel(&kernel_entry);
 883         if (status != EFI_SUCCESS) {
 884                 efi_err("Failed to decompress kernel\n");
 885                 goto fail;
 886         }
 887
 888         /*
 889          * At this point, an initrd may already have been loaded by the
 890          * bootloader and passed via bootparams. We permit an initrd loaded
 891          * from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it.
 892          *
 893          * If the device path is not present, any command-line initrd=
 894          * arguments will be processed only if image is not NULL, which will be
 895          * the case only if we were loaded via the PE entry point.
 896          */
 897         status = efi_load_initrd(image, hdr->initrd_addr_max, ULONG_MAX,
 898                                  &initrd);
 899         if (status != EFI_SUCCESS)
 900                 goto fail;
 901         if (initrd && initrd->size > 0) {
 902                 efi_set_u64_split(initrd->base, &hdr->ramdisk_image,
 903                                   &boot_params->ext_ramdisk_image);
 904                 efi_set_u64_split(initrd->size, &hdr->ramdisk_size,
 905                                   &boot_params->ext_ramdisk_size);
 906         }
 907
 908
 909         /*
 910          * If the boot loader gave us a value for secure_boot then we use that,
 911          * otherwise we ask the BIOS.
 912          */
 913         if (boot_params->secure_boot == efi_secureboot_mode_unset)
 914                 boot_params->secure_boot = efi_get_secureboot();
 915
 916         /* Ask the firmware to clear memory on unclean shutdown */
 917         efi_enable_reset_attack_mitigation();
 918
 919         efi_random_get_seed();
 920
 921         efi_retrieve_tpm2_eventlog();
 922
 923         setup_graphics(boot_params);
 924
 925         setup_efi_pci(boot_params);
 926
 927         setup_quirks(boot_params);
 928
 929         setup_unaccepted_memory();
 930
 931         status = exit_boot(boot_params, handle);
 932         if (status != EFI_SUCCESS) {
 933                 efi_err("exit_boot() failed!\n");
 934                 goto fail;
 935         }
 936
 937         /*
 938          * Call the SEV init code while still running with the firmware's
 939          * GDT/IDT, so #VC exceptions will be handled by EFI.
 940          */
 941         sev_enable(boot_params);
 942
 943         efi_5level_switch();
 944
 945         enter_kernel(kernel_entry, boot_params);
 946 fail:
 947         efi_err("efi_stub_entry() failed!\n");
 948
 949         efi_exit(handle, status);
 950 }
 951
 952 #ifdef CONFIG_EFI_HANDOVER_PROTOCOL
 953 void efi_handover_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
 954                         struct boot_params *boot_params)
 955 {
 956         extern char _bss[], _ebss[];
 957
 958         memset(_bss, 0, _ebss - _bss);
 959         efi_stub_entry(handle, sys_table_arg, boot_params);
 960 }
 961
 962 #ifndef CONFIG_EFI_MIXED
 963 extern __alias(efi_handover_entry)
 964 void efi32_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
 965                       struct boot_params *boot_params);
 966
 967 extern __alias(efi_handover_entry)
 968 void efi64_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
 969                       struct boot_params *boot_params);
 970 #endif
 971 #endif